摘要:为了解大溪水库和沙河水库主要鱼类食物网营养结构的时空变化特征，依据2017年夏、秋季和2018年春季在大溪水库和沙河水库的调查结果，利用稳定同位素方法对这两个水域内鱼类的营养关系进行研究，得到以下主要结论：大溪水库共出现鱼类28种，沙河水库29种，鱼类群落结构组成结构相似，呈现出以湖泊定居性鱼类和鲤科鱼类为主的特征。配对双样本时空差异分析显示，相同季度内两个水库鱼类的δ¹³C值差异显著，说明两个水库的初级食物源存在明显不同；相同区域内，大溪水库季度差异不明显，而沙河水库差异显著，说明大溪水库的初级食物源组成变动较沙河水库的更小。δ¹⁵N值时空变化规律不明显，这可能与水库周围农业活动和人类活动的不确定性有关。鱼类群落指标值分析结果显示，沙河水库的CR、NR、TA、SEAc、CD、MNND和SDNND指标值均高于大溪水库，且春季高于其他季度，这表明沙河水库春季食物网较其他季节、较大溪水库更为复杂，食物源更加丰富，食物链更长，营养层次更多，核心生态位宽幅更低，营养级多样性的总程度更高，营养生态位均匀度较低，大溪水库食物网的冗余程度较高，说明相较于沙河水库，大溪水库生态系统稳定性更高，抗干扰能力更强，这可能与沙河水库周边广泛的茶园、旅游区和和居民区密集分布有关。基于各种量化群落指标对大溪水库和沙河水库的食物网结构进行时空差异分析，能够为大溪水库和沙河水库水生生态系统的管理与修复提供理论支撑。



Abstract:Tianmu Lake is the important water resource in the Jiangsu Province, which is composed by Daxi and Shahe Reservoirs with abundant fishery resource. According to the spatio-temporal variation characteristics of main fishes' food web in Daxi and Shahe Reservoirs, the stable isotope ratio data of species were collected from two reservoirs from July 2017 to April 2018, and the nutrient relationship was analyzed for key species at first time. The results showed that 32 fish species were captured from the surveys, of which 28 fish species were sampled from Daxi Reservoir, while 29 fish species were sampled from Shahe Reservoir. The fish structure communities in two reservoirs were similar, dominated by the sedentary fishes and Cyprinidae. The spatio-temporal differences of δ¹³C value and δ¹⁵N value were analyzed by the paired samples t-test method. The results indicated that there were significant differences of δ¹³C value between the two reservoirs during the same season. There were no significant differences between each season in Daxi Reservoir but opposite in Shahe Reservoir. It means that two reservoirs had various composition of food sources, and that composition of basal resources of fishes in Daxi Reservoir may be more stable than that in Shahe Reservoir. In addition, there were no obvious variations in spatio-temporal of δ¹⁵N value, which may be related to the pollution of agricultural and human activities around the reservoir. The index calculation results showed that range of δ¹³C (CR) and range of δ¹⁵N (NR) in Shahe Reservoir were higher than those in Daxi Reservoir, indicating that the food sources were more abundant and the food chains were longer in Shahe Reservoir. Also, the area of convex hull(TA) and standard ellipse area corrected for small sample size (SEAc) value were higher than Daxi Reservoir, meaning that the trophic levels were more complicated and the core niche space was narrower. Moreover, the mean distance to centroid(CD), mean nearest-neighbor distance(MNND) and standard deviation of nearest-neighbor distance(SDNND) values were also higher in Shahe Reservoir, showing that the overall degree of trophic diversity was higher but lower evenness nutrient niches in it, while higher redundancy in Daxi Reservoir. In addition, seasonal difference analysis results showed that the six index values were higher in spring than other seasons, meaning that the food web structures in spring were more complex. Comparing with Daxi Reservoir, the investigation showed that Shahe Reservoir had lower stability and less anti-interference ability, which may be correlated with the extensive distribution of tea gardens, tourist and residential area around it. Therefore, based on the quantitative index analysis results above, the study could provide adequate theoretical support for the management and restoration of aquatic ecosystem of Daxi Reservoir and Shahe Reservoir.





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb202005261343